1. Field of the Invention
The present invention relates to a circuit substrate, and more particularly, to a circuit layout of the circuit substrate and a light source module applied with the circuit layout of the circuit substrate.
2. Description of Related Art
Due to the characteristics of the LEDs of long lifespan and little electricity consumption, fluorescent lamps and incandescent bulbs are gradually replaced with the LEDs in some fields, such as a scanning light source which requires high reaction speed, a backlight source of a liquid crystal display (LCD) device, car dashboard illumination for a car with front light source, traffic signs, large electronic display bulletins and general illumination devices.
Generally, the series and parallel connection of the LEDs of a light bar is decided by a circuit layout of a circuit substrate while the circuit layout of the circuit substrate is laid out according to the voltage and the current provided by a power supply. However, there are various types of LEDs, that is to say, the driving voltage and the driving current of LEDs are not consistent. Accordingly, the best luminance effect of the light bar is not easily obtained when the light bar is disposed on the laid-out circuit substrate because the circuit layout of the circuit substrate may not comply with the characteristic of LEDs, and thus the appearance and the cost of the circuit substrate is undesirable affected by modifying the circuit layout for making the circuit layout of the circuit substrate comply with the characteristic of LEDs.
For example, if the original circuit layout of the circuit substrate is designed as a circuit with four elements connected in series, the circuit layout is needed to be modified into a circuit with two parallel series each composed of two serially connected elements when the transformation efficient testing is processed. Nevertheless, the series and parallel connection of the elements in the circuit layout is incapable of being modified after the circuit substrate laid-out. Therefore, additional wire jumping, additional wire opening, or re-set up is needed to obtain the required series and parallel connection of the elements in the circuit layout. Accordingly, the manufacturing cost and the time consumption are increased.
In addition, a through hole must be configured in the transmission path of the signal-to-be-measured when the signal or the voltage of the inner circuit in the conventional circuit substrate is going to be measured. The through hole not only has negative influence on the continuity of the upper and lower traces of the circuit substrate, but also renders the trace area and the turning angles increased. Therefore, the interference and the antenna effect between traces in different layers are generated.